1. Field of the Invention
The present invention relates to sheet feeding apparatuses configured to feed sheets and image forming apparatuses, such as a copier, a facsimile (FAX), a printer, and a multifunction machine, that include the sheet feeding apparatuses.
2. Description of the Related Art
Sheet feeding cassettes in which sheets to be used in image forming apparatuses are housed typically have sheet-end-regulating mechanisms configured to regulate the ends of the sheets, such as side regulators configured to regulate the widthwise ends of the sheets housed in the cassettes and trailing-end regulators configured to regulate the upstream ends of the sheets in a sheet conveyance direction.
Such a sheet-end-regulating mechanism is movably disposed on a cassette frame of the sheet feeding cassette, and includes a locking/releasing mechanism with which the sheet-end-regulating mechanism is locked to and released from the cassette frame. Thus, the position of the sheet-end-regulating mechanism can be changed and fixed in accordance with the size of sheets that a user desires to supply to the cassette. An example of such a technique is disclosed in Japanese Patent Laid-Open No. 2002-255358.
FIG. 7 shows an exemplary sheet-end-regulating mechanism. A trailing-end regulator 2, serving as the sheet-end-regulating mechanism, will now be described.
The trailing-end regulator 2 has a regulating surface 2a at which the trailing ends of sheets are regulated, a rear plate 4 on the side opposite the regulating surface 2a, and projections 3 at the bottom. The projections 3 slidably engage with rails provided in a cassette frame (not shown), whereby the trailing-end regulator 2 is movable in a sheet feed direction. The trailing-end regulator 2 also has a stopper 6 integrally provided thereon and with which the trailing-end regulator 2 is locked to the cassette frame. The stopper 6 is turnably supported by the rear plate 4 with an elastic rib 8 interposed therebetween. The stopper 6 includes a release lever 7 handled by a user, and a locking projection 9 engageable with a rack provided on the cassette frame, the rack extending in a direction in which the trailing-end regulator 2 moves.
To move the trailing-end regulator 2, the user pinches the release lever 7 of the stopper 6 and the rear plate 4 of the trailing-end regulator 2 together, whereby the elastic rib 8 bends and the stopper 6 turns. This disengages the locking projection 9 from the rack (not shown) of the cassette frame, allowing the trailing-end regulator 2 to move.
In such an operation of moving the trailing-end regulator 2, however, the release lever 7 and the rear plate 4 are to be kept pinched together with a plurality of fingers.
Even if it is attempted to push the trailing-end regulator 2 at the rear plate 4 from the left side in FIG. 7 so as to avoid pinching with fingers, a large physical force is used to move the trailing-end regulator 2, resulting in poor operability.